Megasquirt owners thread

[Cus]

Anecdotally, the tacho seems to be more accurate, at 2/3/4k the needle is at least on the line when TS says the RPM is at these numbers. There is a very large chance it's the "I worked on the car and now it runs better placebo" effect in full swing though, it was only about 100RPM out before-hand.

I have to agree with Red_Bullet, the MS isn't secret tuner's business, if anything it's the opposite where there's too much information available, and it becomes very easy to get very confused very quickly. A lot of the time I get to a point where I just take the laptop to the car and start trying things so I can get an idea of what happens, then I go back and read some more to make sense of what I've discovered. When I have a tune that works, I save a copy of it somewhere so I can go back to a known good setup in case the experimentation gets too far out of hand.

I've always lived by the motto "the stupidest question is the one that's never asked" - it has led to some incredibly stupid questions, but I'm fine with that. In our current hyper-connected society someone else has already asked "the stupid question", and 90% of the time I can just google an answer and move on. The rest of the time results in a post about something random on here

Where it gets interesting with the MS, and MX5's in general, is there is 27 years of knowledge on the internet about mx5's, and 16 years of megasquirt, and every new model of both is slightly different, so here I am with a 26 year old car and a 4 year old ECU, and doing google searches often comes up with things that worked 10 years ago on a 16 year old car with a 2 year old ecu, but is "wrong" for me.

All I knew about engines before starting the MS adventure was "suck, squeeze, bang, blow" and "14.7 is the AFR you want" I made it start, idle, accelerate and cruise. I've got my CL-Idle tuned to the point that MAT actually affects the AFR. I have the VE table dialed in in the important places (ie; AFR error of 0.1 at most while doing WOT pulls) I still have no idea how to setup the MAT correction tables (my next project) or how to stop the stupid stumble on a throttle-jab from idle, my Accel-Pump settings are not even close to being right, I can either make them too rich, or too lean. Somehow at the moment, it's both. I've solved that problem by being gentle on the throttle for the time being.

The ECU still does things I don't even know about, let alone comprehend (X-Tau, anyone?) And that's why I like it. The more I learn, the more there is to learn!

[Red_Bullet]

Scatter Plots.
Has anybody been using scatter plots?
Here is one of mine showing MAP*RPM, Duty cycle, AFR.
There seem to be two lines, I understand it's desirable to have one tightly defined line. So, I'm wondering what is causing the upper (richer) line. This plot is from a lot of data gathered driving to a track day, then home again, quite a lot of data.

My thinking is that the upper line may be caused by Accel enrichment OR transitioning out of throttle as the MAP falls quickly. Looking forward to being enlightened.



Scatter plot AFR CROPPED by Keith Wade, on Flickr

[Red_Bullet]

No takers?

Here is some background info. Worth a look I think. Seems like a great tuning aid.

http://www.tunerstudio.com/downloads2/2013_MegaMeet-Tuning_with_ScatterPlots.pdf

https://www.youtube.com/watch?v=tijfx9pqgsU

[Cus]

I've played with scatter plots a small amount, but they're a little bit too "down the rabbit hole" for me at the moment.

Change the right graph to Y=MAP, X=RPM, Z= AFR, then click on the lines on the left, and see where you get dots on the right, that should at least show you where they're happening in the map.. I'll fire up the laptop and see what I get out of a log

*hold music begins playing*

[Cus]

*hold music stops*

"Thank you for holding, your call is important to us."



The higher line on mine is the 5kRPM non-WOT section of the map, which was wildly lean (AFR 17+ while "crusing" in 3rd) after messing about with the intake.

The blue tail in the top half is the is the WOT/100kPa values.

So, at a guess, that means you're leaner randomly in one part of you map? (wild guess based on a datapoint of one log)

[Red_Bullet]

Scatter plot AFR CROPPED 2 by Keith Wade, on Flickr

I've only just started playing with scatter plots myself. I think I need to turn off accel enrich, run around and get plenty of data, VE analyse that, load the new calculated ve table, run around again, get plenty of data, if it looks ok, then and only then re add accel enrich. Then have another look at these plots. There is plenty here to keep me busy for another good while it seems.

[StanTheMan]

Give started looking at it. But not managed to make sense of it yet.
But by the looks of it, my map is still way out, nowhere near as clean as above.

[bartmanftw]

Anyway, for clarification, here is quickly drawn up "mud map" schematic. Hope this helps. A picture paints a thousand words. This is for a 1994 NA8.

Tacho circuit by Keith Wade, on Flickr

Option 3 is what Cus has done except the ECU supplies a 0-12V signal so no need for a pull-up resistor. This is the neatest way to do it imo.

The two different lines may be due to different air temps and incorrect corrections or a change in altitude causing different AFRs. Just guessing but you should be able to incorporate air temp data into the scatter plot to find out.

[Red_Bullet]

Thanks for the clue bartmanw about air temp, it got me looking, and I have found this... This is braineac's (from Miata Turbo Forum) MAT correction table, way different from the default which I'm using. Braineac seems to be the guru over there. Interesting discussion on this on MT. Link below.

http://www.miataturbo.net/megasquirt-18/what-does-your-mat-air-density-table-look-like-89026/page1/


[url][url=https://flic.kr/p/S8Neau][/url]ideal_MAT_curve_custom by Keith Wade, on Flickr[/url]

[StanTheMan]

ohhhh ƒü¢k

Honestly I wasnt doing much.......
not that there is anything wrong with Arabic

Screenshot 2017-02-21 14.50.20.png

I just cant read Arabic

Could someone look & tell me how to get it back to Engrish?

[Lokiel]

Options (2nd column of top menu bar) -> Language (first item in drop-down list) -> English (probably the first option in the Language list; you should be able to see it listed)

Mine went "Arabic" too once - unlike Pauline Hanson or "Trumpty Dumbty", I didn't blame it on Islamic terrorists.

[noobee]

a picture

Screenshot (1).png

[StanTheMan]

awesomeness


Thank you.

major meltdown at my house avoided.

[StanTheMan]

One more thing.

I get an error when I load Tuner studios
Warnings:

Warnings:
Warning: Unknown 5th position attribute: =, known field Attribute: displayInHex, Problem at:
[mainController.ini]:[Line:3116]: field = "Soft limit Retard to", launch_sft_deg, {launch_opt_on } field = "Launch retard above", launch_sft_lim, {launch_opt_on >0}

how can I get rid of that? without always pressing the ignore button

[Red_Bullet]

Maybe it's something in here: Advanced Engine/Launch Control
Please note I don't have this setup, but here are my settings, maybe there is something wrong in yours.